A TRIUMPH FOR TURTLE TEAM

Release of zoo-raised reptiles into the wild a project milestone

A coalition of three agencies and the San Diego Zoo have a message for the public: Think twice before you abandon your unwanted critters in the backcountry because this is a leading cause of harm to the ecosystem.

The alliance has been working to remove those non-native species — such as largemouth bass and bullfrogs — from areas that have suffered such damage. Their goal is to help revive populations of embattled native animals, including Western pond turtles and tree frogs, so nature can regain its balance.

The team reached a milestone this month with its first release of Western pond turtles, the only turtle species native to California, in the Sycuan Peak Ecological Reserve near the Cleveland National Forest in East County. The five turtles were painstakingly raised for three years before their introduction to the wild.

“(Western pond) turtles have been here for well over 10,000 years. They are part of Southern California’s landscape,” said Thomas Owens, senior herpetology keeper at the San Diego Zoo.

Other members of the coalition are the U.S. Geological Survey, the California Department of Fish and Wildlife and the San Diego Association of Governments, or SANDAG.

Funding for the turtle restoration includes two SANDAG grants totaling $284,000; the money comes from TransNet, the region’s half-cent sales tax that goes mostly to transportation projects but also covers some environmental programs.

In addition, the zoo has received private donations for its reptile initiatives, including the turtle rearing. It declined to specify the amount or the contributor.

For much of the past decade, researchers have identified the turtles as a species on the brink of extinction in Southern California. The U.S. Geological Survey has conducted searches for them and couldn’t find any until nearly four years ago — after they and the other alliance members had begun their breeding project.

Various factors have caused the pond turtle population to almost vanish in the lower half of the state, including the turtles’ shy and protective demeanor as well as people introducing non-native predators into their habitat.

“A lot of people may go to an area in the north coast and see a lot of turtles,” said Chris Brown, a reptile ecologist with the USGS Western Ecological Research Center who has been studying the turtles for many years. But in San Diego County, the denser human population and the high impact of non-native species in certain areas have nearly wiped them out.

During their monitoring, scientists set traps for pond turtles but often returned to discover lots of African clawed frogs — a non-native species. In 2009, they found a population of 30 to 45 turtles, including three juveniles, within the Sycuan Peak reserve.

The Geological Survey have removed non-native predators while trapping mature female pond turtles for the San Diego Zoo’s “headstart” program. Zoo researchers raise the resulting hatchlings, which measure no larger than a quarter, until they’re big enough to defend themselves. After they reach the size of an iPhone, biologists release them into the reserve.